Working Voltage: 2.7V-4.2V, suitable for NCM Ternary polymer lithium battery (Li-ion), lithium iron phosphate battery (LiFePO4). It can Not fit LTO battery. If it is used for 3S, the last line B4+ is empty. Working Principle: Flying capacitor transfer charge transporter, Balancer board is connected to the battery to start the balance work, using the original brand new ultra-low internal resistance MOS, 2OZ copper thickness PCB, balance current 0-5.5A, the more balanced the battery current is Small, reserved for the dormant switch wiring position, the dormant power-off mode working current is less than 0.1mA, and the balance voltage accuracy is within 5mv! The quiescent current is about 12mA, and the battery capacity is recommended to be used between 30-300AH! With under-voltage sleep protection, only detecting the battery voltage of B1, the equalizer will automatically stop entering the sleep state when the B1 voltage is lower than 2.7V, and the standby power consumption is less than 0.1mA. Note: Before connect the balance cable to the balance board, be sure to check whether the connections of each section of the battery pack are correct, and do a good job of insulating the bottom of the board and the battery string connection terminals. Otherwise, it will short-circuit and burn the board. Technical Parameters: Working voltage: 2.7V-4.2V, suitable for NCM Ternary polymer lithium battery (Li-ion), lithium iron phosphate battery (LiFePO4). Working principle: Flycap-capacitor transfer charge transporter, Balancer board is connected to the battery to start the balance work, using the original brand new ultra-low internal resistance MOS, 2OZ copper thickness PCB, balance current 0-5.5A, the more balanced the battery current is Small, reserved for the dormant switch wiring position, the dormant power-off mode working current is less than 0.1mA, and the balance voltage accuracy is within 5mv! The quiescent current is about 9mA, and the battery capacity is recommended to be used between 30-300AH/Per Balancer. With under-voltage sleep protection, only detecting the battery voltage of B1, the equalizer will automatically stop entering the sleep state when the B1 voltage is lower than 2.7V, and the standby power consumption is <0.1mA. Board size: 2.6x1.8x0.63inch Balance cable length: 1.31ft One LED indicator: It will always be on during normal operation, but it will not turn on when there is a problem or malfunction. RUN pad: you can add a switch to control the balancer. Default short connect, let balancer working. if disconnect, it will not working. Note: 1. Please start wiring from the total negative pole, followed by B-, B1+, ... B4+.(Test per string battery voltage whether is right before connect to Balancer board). 2. The time required for equalization mainly depends on the battery capacity. Package Includes: 1x 4S Balancer Board 1x 5Pin Cable